Embodiments of the inventive concept relate generally to semiconductor memory devices. More particularly, embodiments of the inventive concept relate to three-dimensional semiconductor devices and related methods of operation.
Over the past several decades, researchers have made continual improvements to the performance, storage capacity, and cost of semiconductor memory devices. One of the primary techniques for making these improvements is increasing the integration density of the devices.
One of the most common ways to increase the integration density of a semiconductor memory device is through miniaturization. In other words, reducing the feature size of a device enables more memory cells to be formed in a unit area of a device, which can increase its speed and storage capacity, while reducing the cost per bit of storage.
Device miniaturization is limited by manufacturing technologies. For instance, to form a semiconductor memory device with high integration density, a manufacturing apparatus must be able to create fine patterns in the device. However, it is extremely expensive to improve the precision of such manufacturing apparatuses.
In an effort to improve the integration density of semiconductor memory devices despite the limits of manufacturing technology, researchers have developed three-dimensional semiconductor memory devices, which store data in a three-dimensional grid. To justify the mass production of three-dimensional semiconductor memory devices, manufacturing technologies must be able to decrease their manufacturing cost per bit compared with two-dimensional semiconductor memory devices.